Vegetable oil, particularly oil extracted from seeds, is an important agricultural commodity. Currently, most of the vegetable oil that is produced is directly or indirectly consumed by humans. Because the oxidation of vegetable oils can lead to undesirable odors and flavors in the oil that consumers find unpalatable, agricultural scientists initiated efforts to improve the oxidative stability of vegetable oils. The scientists have significantly improved this aspect of oil quality. The oxidative stability of the vegetable oil is primarily related to the number of double bonds in its fatty acids. That is, fatty acids with several double bonds are known to be more unstable than fatty acids with fewer double bonds. Thus, scientists have worked to improve shelf life and oxidative stability by reducing the amount of the trienoic fatty acid, α-linolenic acid.
Other work has concentrated on producing oils with specific fatty acid compositions. Recently, medical science has provided evidence that the replacement of fats in the human diet with oils rich in the monounsaturated fatty acid, oleic acid, is beneficial to human cardiovascular health. Medical and nutritional experts alike are now advocating the replacement of fats in the human diet with oils rich in the monounsaturated fats. As a result of the increased demand for oils rich in monounsaturated fatty acids, agricultural scientists have concentrated their efforts on developing new plant varieties for the production of vegetable oils that are rich in oleic acid. High-oleic canola (Brassica spp.), safflower, and sunflower oils are now available.
More recently, agricultural scientists have initiated efforts to genetically engineer crop plants to produce seed oils containing unusual fatty acids, such as epoxy and hydroxy fatty acids. Primarily, scientists have initiated these efforts to produce oil containing such fatty acids for use in industrial applications. Such fatty acids find use as plasticizers, lubricants, surfactants, components of paints and renewable raw materials in a myriad of industrial syntheses. One goal of the scientists is to develop renewable replacements for the non-renewable, petroleum-based, raw materials upon which industry currently depends. Thus, in the future, vegetable oils with unusual fatty acids are likely to increase in industrial importance as the world's finite petroleum reserves diminish.
While some progress has been made in the genetic engineering of crop plants for the production of seed oils with unusual fatty acids, agricultural scientists have experienced difficulties in achieving levels of these fatty acids that make the industrial use of the oil economically practical. The challenge remains for agricultural scientists to increase the levels of the these fatty acids in the seeds of crop plants used for oil production.